Hey all-
My 05 5.4 Supercab 4x4 is now getting about 10mpg. I just had the plugs changed, and a new air filter. Dealer says the autolite plugs I put in could be the culprit, but I don't see how. He also suspects old fuel filter. Anybody had this kind of problem?
Thanks
T

 

Many complain of poor fuel mileage on their 5.4's. If you did a search on "gas mileage" or "MPG", you'd see tons of responses on this.....

Was the mileage better before the plug change (I'm discounting the fuel filter)?

 

What kind of driving do you do?

 

Arent fuel filters supposed to be changed every 30k? I would change mine if you havent done so in the last 30k. Same with the tranny...the fluid couldve degraded to a point where it doesnt efficiently transfer the power from the engine to the tires.

And you should post the specs on your truck. Lifted trucks with bigger-than-stock tires obviously hinder fuel mileage.

 

Thanks-
I do have a 2 1/2 inch leveling kit on the front, and run Michelin LTX MS 265-70 17's. My driving is a combo of street and highway, I am a GC and I travel all over town checking my projects. The Michelins are great tires, and are about 1 size up from stock. The best thing about this truck is despite being a 4x4, it is quiet and smooth on the highway. I will look at what you guys have pointed to, and make improvements, to see if the mileage gets better.
T

 

Do you do a lot of city driving? My town mpg is 11mpg, but I just got 16.5mpg on all highway with no changes.

 

I'd say that 10mpg is a bit on the low side for mixed driving but you do have a lift and a slightly larger set of tires. Are you hauling much stuff around? Lead foot?